Between those two cards, the best bang for the buck would be the 7970. But honestly just wait till the release of 7950 and see if you can crossfire though. Those might be slightly more expensive but will outperform a single 7970 by a wide margin.
Sounds like drivers issues which will be corrected by new drivers. Shouldn't let these issues change your mind as they will be eliminated as the drivers for the 7970 mature.
I'd say its drivers too for the HD7970/HD7950, but that shouldn't stop you from buying one. Its because it uses quite significantly different hardware to previous gens, the downside being the short term issues which you may be able to work around, the long term upside is there's probably quite a bit of potential left in terms of performance, something which the 580 won't have. Of course, you then have the superior energy efficiency of the HD7970 to consider.
Neither. If you buy now for single monitor a GTX570 will do the trick for far less money. That's best bang/buck. If you can get a 580 for 460-480$ then it's a better deal than a 550$ 7970. If not the 7970 is the way to go.
I got 2 580s for 340 each from a person in TPU, sweet deal for me. If you do get a 580 then you should look into doing the same. A lot of people are jumping ship for the 7970 and selling off their hardwares real cheap. Or if you want a 570 then buy my one lol.
Dont buy any,stick with what you have and wait for the new nvidia cards to come out,in 2-3 months which isnt long.Even if you dont like the new nvidia cards that come out the 580's are bound to drop in price so you could grab one then if you wanted,but buying now is unwise,its up to you.
http://www.newegg.com/Product/Product.aspx?Item=N82E16814125399 If You Even consider a 580gtx get the 3 gig version. I Have this card and it's amazing. 55-60c max load without messing with fan speeds. crysis 2 ultra bf3 ultra are simple tasks with this one at 1080p
I got 2 GTX 560 1gb for 300€, no driver issue in any game and it really kicks ass. Got the Gigabyte OC version (not SOC) and they are really silent. Check them out!
ATI for rough power NVidia for driver support 580 or 670 if you do lot of thing, 7970 if you only game (but take care that where we live (moi aussi) ATI is more expensive than NVidia for the equivalent product)